When a jet-powered aircraft lands, the landing gear brakes and aerodynamic drag (e.g., flaps, spoilers, etc.) of the aircraft may not, in certain situations, be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the braking of the aircraft. When deployed, a thrust reverser redirects the rearward thrust of the jet engine to a generally or partially forward direction to decelerate the aircraft. Because at least some of the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Many of the thrust reverser designs include brake/clutch assemblies to inhibit unintended movement of the thrust reverser or actuators that move the thrust reverser. The assemblies may incorporate disk brakes or cone brakes that are coupled to conventional ball or roller clutches. The clutches typically include a rotatable shaft that extends through a stator, and rolling elements, such as balls or rollers, that are disposed therebetween.
Many times, a groove is included on one or both of the shaft and stator that provides a wide and a narrow gap therebetween. The wide gap allows the rolling elements to roll therein when the clutch is unlocked, and the narrow gap pinches the rolling elements between the shaft and stator when the clutch is locked. The rolling elements are further secured axially in the groove by a retaining force supplied by a spring or other source.
In some cases, a force may be exerted on the rolling elements that causes an extended period of pinching and/or unintended sliding between the various contact surfaces. As a result, the brake/clutch assembly may become worn. Alternatively, the rolling elements may become jammed against the stator and/or shaft, and the system may not operate properly. In other instances, such as when the brakes are reengaged after deployment of the thrust reverser system, the clutch may internally overrun which may cause one or more of the rolling elements to become displaced or misaligned with respect to adjacent rolling elements.
Hence, there is a need for a clutch assembly that experiences minimal wear during operation and has rolling elements that, if displaced or misaligned, do not affect the operation of the assembly. Additionally, it would be desirable for the assembly to be operable with various types of brakes. The present invention addresses this need.